Split Boil Numbers

[rodwha]

I bought a 5 gal water cooler to better hold temps for all-grain. As I found out I shorted myself on the sparge water as my pot only handles 6 gals.

I still have 5 brews worth of ingredients but have had my hobby funding pulled for now. I'm considering mashing the remainder I cannot handle (2 batches worth) and setting it in my fermentation chamber.

I'm trying to figure out whether or not I'd need to boil the additional bit longer or shorter to end at my desired volume (5.25 gals). My boil off rate hasn't been nailed down as it seems to fluctuate between 1-1.25 gals/hr.

To better figure the volumes I'm wondering what the minimum volume of sparge water I'll need to achieve a basic 75% efficiency on 7 lbs of grains that I'll be doing a 1.25 qt/lb mash on (I'll actually round up to 9 qts).

For my mash tun I've been using my BIAB grain bag as the filter and modified the spigot to use a bottling bucket spigot. Due to this setup I found I had draining issues potentially due to the grain bag resting on the spigot so I've dropped a metal rack from a pressure canner that kept the pot from sitting on the base. This gives me dead space of about 1 qt.

I keep my sparge water in my brew pot until I'm about ready to drain the tun in which I split this water between 2 pots and my 1 gal pitcher (about 3 gals total) and then pour one until it's about done draining.

Maybe there is a more efficient way to sparge too? Fill it back up and allow it to sit a moment instead of freely draining it into the brew pot?

 

[chickypad]

I'm kinda confused what you are asking. I think you are saying you can't fit a full boil in your 6 gal pot for a 5.25 gal batch, so you want to split the boil into 2 pots and you need help with the math? Most folks I've seen doing this split the hops between the two evenly, then just treat it like a full boil. The only difference in the calculations that way would be accounting for the extra boil off of the second pot. You do need to know the boil off rates so you can figure out how much sparge water to get your total boil volume.

The other option would be to do a concentrated wort in your big pot (should be able to get 4 gals I would think) then just top off with 1.25 gals of water and not mess with the split boil. I do that sometimes brewing 3 gals and topping off to 5, I take about a 5-7% efficiency hit though.

Batch sparging would be simpler with your system I think. Just dump the sparge water in a bucket (it doesn't need to be that hot), drain the first runnings fully into the kettle, then dump in all your sparge water. You do need to stir the crap out of it when batch sparging.

 

[rodwha]

It's because of my pot volume that I cannot mash and sparge well more than 7 lbs of grains and a typical recipe calls for about 11 or so pounds.

When doing partial mashes I liked a 1.5 qt/gal ratio but now I've reduced it to about 1.15 qts, though I did further modify the rack I placed in my tun so that it leaves less dead space (I bent a leg all the way down so that it's nearly touching the bottom).

As 11 lbs would call for about 14 qts that would leave me with only 10 qts to sparge with which gave me a very low efficiency to where I had to use 2 lbs of DME to reach my low 5% ABV target (I dislike light beer) as it would have been just below 4%.

So what I'm considering as I'm not sure when I'll get my hobby funding reinstated is to take the 4 lbs of 2-row that won't fit and mash/boil it in advance, maybe putting it to the fermenter I'll use and storing it in my chamber until the rest is processed.

To make this more efficient I figured I could try processing 8 lbs (pushing it maybe) and splitting that so I don't have to do this so often.

I'm wondering what the minimum amount of sparge water I'd need to hit about 75% efficiency of 7 (or 8) lbs of grains this way. It seems I need at least about the volume required for mashing, but I'm not sure.

I've not tried stirring. I'll do that next time. I used to use a strainer and squeeze the grain bag which got me 80-85% efficiency when doing ~6 lbs of mashing (partials).

 

[chickypad]

Okay, so you're wanting to do a split mash and boil and combine the resulting worts into one batch in the fermenter. A normal sparge volume would only be about another 1.25 to 1.5 gal maybe. Do you not have a second pot in your kitchen that would fit in? If not I would still just mash once, do the full sparge but collect that extra 1.5 gal in a bucket. You can add a bit to the boil kettle as it boils off room, then do a short boil on the little bit that's left and add it at the end. Seems a lot easier than doing 2 full mashes. I think any differences in hop utilization would be minimal.

 

[rodwha]

Once the mash is over I pour from my brew pot the sparge water into two pots (~1 gal each of water) to keep warm and fill my 1 gal pitcher with the first sparge. This takes up the whole stove at that time.

I do have my old 5 gal pot that I made a koozie for to save space, but I got expanding foam on it. I've thought about sanding it off in case I ever wanted to heat it up again but haven't bothered.

I have to straddle two burners to get a good boil, as well as use the perforated tomale bottom as a lid propped up by my spoon to get 5+ gals to boil. Sorry glasstop... And this is with cheap thin aluminum pots.

Once the sparge is over (and I've cleaned up the 5 gal pot) I could certainly boil the remainder of the mash at the same time, and a better idea I believe as I won't need to consider how wort I'd doing without yeast working on it.

I think I'll work on that old pot to see if I can get the foam off it well enough and try that.

Thanks!

 

[chickypad]

Once the mash is over I pour from my brew pot the sparge water into two pots (~1 gal each of water) to keep warm and fill my 1 gal pitcher with the first sparge. This takes up the whole stove at that time.

Are you then batch sparging then with that water, or doing some kind of pour/fly sparge? That does sound a bit cumbersome, I would definitely switch to a single batch sparge. Just heat the water to 150 or so, doesn't have to be too hot with batch sparging, then dump it all in a bucket. Drain the tun fully, add all the sparge water and stir the crap out of it, then drain fully again. I've always gotten very good efficiency this way, pretty much the same as with my big rig and fly sparge set up.

 

[rodwha]

I'm not keen on the various types of sparging jargon.

What I had done, and am doing now, is to pour sparge water and allow it to drain and then repeat for as much water as I have (3 containers now). I've not allowed it to sit as when I first did mashing I used a very large colander to hold 6 lbs of grains and just kept pouring until I reached saturation and waited a while and repeated. I got good results (80-85%) this way and just went with it when I transitioned. I'm now pressing the grains as I used to do at the end. After its all said and done I allow gravity to get what else it can and just add it periodically.

Oddball way to do this I know...

 

[chickypad]

It sounds like you are describing fly sparging, where you continuously rinse the grainbed without stirring. Another way is to batch sparge, where you run the mash tun dry into the kettle, then add all the sparge water at once, stir the crap out of it, then run that all into the kettle. With your set up it just sounded easier to batch sparge.

 

[rodwha]

I've been figuring numbers and contemplating...

If grain absorption is roughly 0.125 qts/lb (1.375 qts for 11 lbs) this won't put me too far beyond my 6 gals (I've not worried about the absorption loss I guess because it was minuscule during my 6 lb partial mashes). I'm thinking I'll add 1.5 qts to my 6 gals I treat and split the volume 13.5/12 qts (mash/batch sparge) if this ought to get me at least 75% efficiency.

My main question, if this is suitable, is how long would I need to stir and how long should I allow it to be until I drain it?

If this works I won't need to boil in another pot. I'm hoping it is sufficient as I couldn't get the foam off of my old pot well enough and am afraid it may mess up glasstop stove.

I do have a 7 qt pot (claimed to be 8 but it's false as is my "8" gal brew pot that only holds about 7. Guessing the Chinese cannot figure liters to gallons or something.

 

[chickypad]

It's .125 gallon per lb (or about 1/2 qt) for grain absportion in a regular tun, or about .08 gal per lb for BIAB with squeeze. You're going to lose about 1.37 gals, or around .9 gals if you squeeze. But it's still the boil pot that is the rate limiting issue for you, unless you split the boil you can't boil more than about 5 gal to start with.

With batch sparging after you stir the crap out of it for a few minutes you don't really need to let it sit. Vorlauf if you want but then let it rip.

 

[rodwha]

I guess I need to measure water levels and mark them with an awl in my pot. I wouldn't have thought I lost quite that much, though I guess I could see it being more difficult to notice with nearly half the grains.

I'm thinking of tryin my 5 gal pot with an edge hanging off of the burner (the end I can't get cleaned up well enough). Surprised course emory cloth isn't working as well as I figured.

 

[rodwha]

I have been pressing the grains and will try using a small pot lid to see if it improves the output.

I'll be brewing a lower gravity beer later this week and will see how 8 lbs at 1.25 qts/lb works and work my way up until I have issues. I don't mind small amounts of top off (up to 1/2 gal) but don't want to go below about 75% efficiency.

 

[rodwha]

My projected OG was 1.049 but ended with 1.056.

I'll b feeling confident with my next brew increasing from 8 lbs to 9.5 lbs of grains. Seems the 11 lbs I had initially set my latest brews at would be within reason.